Homogenous ductile nickel base alloy weld deposit and method for producing same



April 1966 J. F. QuAAs ETAL 3,246,981

HOMOGENOUS DUGTILE NICKEL BASE ALLOY WELD DEPOSIT AND METHOD FORPRODUCING SAME Filed Feb. 27, 1964 3 Sheets-Sheet 1 PRIOR ART INVENTORSJaseph F. Quaas 9r Um'el; P. Tanzman ATTORNEYEB April 19, 1966 J. F.QUAAS ETAL 3,246,981

HOMOGENOUS DUCTILE NICKEL BASE ALLOY WELD DEPOSIT AND METHOD FORPRODUCING SAME Filed Feb. 27, 1964 5 Sheets-Sheet 2 PRIOR ART iNVEMTORSJoseph FQuaas anieL RTmzzman ATTORNEYS April 19., 1966 J. F. QUAAS ETAL.3,246,931

HOMOGENOUS DUCTILE NICKEL BASE ALLOY WELD DEPOSIT AND METHOD FORPRODUCING SAME Filed Feb. 27, 1964 3 Sheets-Sheet 5 PRIOR ART ATTORNEYS,Joseph FQuzms&

Daniel, P Tanzman BY/ M AT'mRNEYs United States Patent HOMOGENOUSDUCTILE NICKEL BASE ALLOY WELD DEPGSIT AND METHUD FOR PRODUC- ING SAMEJoseph F. Quaas, Island Park, and Daniel I. Tanzman, Far Rockaway, N.Y.Filed Feb. 27, 1964, Ser. No. 347,945 16 Claims. (Cl. 75170) Thisinvention relates to a method and metal powder for welding joints andmore particularly to such a method and metal powder for flame sprayingjoints.

Although conventional metal powders can be satisfactorily deposited on,for example, joints at acceptable temperatures, these deposits are notas ductile as desired.

An object of this invention is to provide a method and metal powder forwelding in which the metal powder possesses advantageous characteristicssuperior to conventional materials with improved ductility also.

A further object of this invention is to provide such a method and ametal power which is applied with low cost deposition.

In accordance with this invention, nickel powders of finer than 150 meshare added to a lower melting nickel base alloy powder to obtain aheterogeneous mixture in which the nickel powders comprise from 10 to50% by weight of the mixture. The mixture is simultaneously flamesprayed and fused to obtain a homogeneous ductile deposit. Surprisingly,the melting temperature of the mixture is substantially that of thenickel base alloy although the nickel powder itself has a higher meltingtemperature and comprises such a relatively large amount of the mixtureor filler metal. However, the resultant deposited metal has vastlyimproved ductility over the nickel base alloy alone. The superiorqualities of the pure nickel are thereby obtained in the deposit atlower temperatures because of the interreaction between the purenickeland the alloy. In an advantageous form of this invention the nickelpowders comprise from 30 to 40% of the mixture.

Novel features and advantages of the present invention will becomeapparent to one skilled in the art from a reading of the followingdescription in conjunction with the accompanying drawings whereinsimilar reference characters refer to similar parts and in which:

FIG. 1 shows the microstructure of a conventional nickel base alloy;

FIG. 2 shows the microstructure of the nickel base alloy shown in FIG. 1after deposit in accordance with this invention with nickel powdersadded;

FIG. 3 shows the microstructure of another nickel base alloy;

FIG. 4 shows the microstructure of the nickel base alloy shown in FIG. 3after deposit in accordance with this invention with nickel powderadded;

FIG. 5 shows the microstructure of still another nickel base alloy; and

FIG. 6 shows the microstructure of the nickel base alloy shown in FIG. 5after deposit in accordance with the invention with nickel powder added.

In FIG. 1 is shown the microstructure of a nickel base alloy containingthe following composition: 2.6% Si, 1.5% B, 0.5% Fe, 0.03% C. FIG. 2shows the same alloy after a 30% addition of nickel powder and depositin accordance with this invention. As shown in FIG. 1, the grains 10 ofnickel are relatively small as compared with the much larger grains 12shown in FIG. 2. The proportion of the hard intergranular constituentsin FIG. 2 are reduced to a level which permits the alloy to possessgreater ductility and lower indentation hardness as a result of theaddition of pure nickel powder.

Similarly, FIGS. 3 and 4 show the effect of a 40% addition of nickelpowder to NiB-4 nickel base alloy containing the following composition:3.54% Si, 2.02% B, 0.45% Fe, 0.04% C. As shown in FIG. 4 the resultantnickel grains 14 of the nickel solid solution after deposit inaccordance with this invention are exceedingly larger than the nickelgrains 16 shown in FIG. 3. The microstructure shown in FIG. 4 indicatesthe greatly reduced amount of hard intergranular constituents whichthereby results in vastly improved ductility.

FIGS. 5 and 6 show the effect of a 30% nickel powder addition to NiB-l,nickel base alloy containing the following composition: 14.9% Cr, 4.3%Si, 3.4% B, 4.2% Fe, 0.68% C. As compared with the very hard deposithaving small nickel grains 18 shown in FIG. 5 the large nickel richgrains 20 shown in FIG. 6 of a deposit in accordance with this inventioncontain boron, silicon, and iron in a solid solution and indicate theimproved ductility and lower indentation hardness of the heterogeneousmixture.

This improved ductility is obtained with the retention of the desirablequalities, such as the ability of being deposited at satisfactorymelting temperatures, of conventional nickel base alloys by adding from10 to 50% by weight of nickel powders to the nickel base alloys. Some ofthe advantageous nickel base alloys are described as NiB-l, NiB-Z, NiB-3and NiB-4 in Table I, page 4 of the American Welding SocietySpecification A5.862T. The resultant nickel mixture is particularlyeflective when it is sprayed and fused in a single operation on, forexample, a joint by using for example a conventional flame sprayingtorch or a flame spraying torch of the type described in copendingapplication. Serial No. 289,474, filed June 21, 1963, or a torch of thetype described in US. Patent 2,786,779 to obtain a low cost homogeneousnickel deposit having a higher remelt temperature than the temperatureat which the heterogeneous powder mixture is applied such asapproximately 2400 F. Surprisingly, the nickel mixture has, uponspraying, excellent wetting-on flow characteristics.' This result isparticularly unexpected when the much higher melting point of the powderis considered. For example, the melting point of the pure nickel is 2652F. as compared with an alloy melting point of 2400 F. However, where thenickel powders are of particle size finer than 150 mesh, the power isvery rapidly taken into solution at the temperature normally used todeposit the nickel base alloy itself. A fluid molten pool is therebyproduced which ,wets the base metal and can be manipulated verysimilarly to the nickel base alloy involved. That the molten pooldissolves the nickel completely is proven by the fact that nosegregation of nickel has been found in the microstructures of numerousdeposits made with up to 50% nickel powder addition. FIGS. 2, 4, and 6,for example, show that the microstructure produced by nickel powderadditions is characterized by greater solution of the hard constituents.

The following table shows the effect of nickel powder additions onlowering the hardness of the nickel base alloy powder containing thefollowing composition: 2.6% Si, 1.5% B, .5% Fe, .03% C.

I Mixture Weight percent Rockwell B hardness nickel powder 1 0 RB 93-982 10 RB 90-91 15 RB 86-89 4 20 RB 78-82 30 RB -78 40 RB 65-70 50 RB57-62 As is readily apparent from the preceding table, sub- 35 stantialreductions of deposit hardness are obtained with the use of theheterogeneous powders, especially where the powders constitute at least10% by weight of the mixture. Further, the consistency of hardnessvalues along with the length of a given deposit clearly indicates thatthe powdered nickel has gone completely into solution.

The following examples illustrate mixtures that satisfy the objectivesof this invention:

Example 1 NiB-l Nickel powder Weight percent 90-50 10-50 Preferredmixture, percent. 70 30 Mesh size range 150 150 Preferred mesh size-150+400 -200-]-400 Example 2 N iB-4 Nickel powder 90-50 10-50 60 40 100-l50 Preferred mesh size 150+400 -200+400 Example 3 Nickelbron- Nickelsilicon alloy powder Weight percent 90-50 10-50 Preferred mixture,percent 70 30 Mesh size range -150 150 referred mesh size 150+400200+400 An advantageous nickel base alloy is:

Constituent Rangeto-Preierred range Example,

percent 5. 0-15. 0 13. 0-15. 0 14. 9 2. 0-5. 0 3.0-5. 0 4. 3 1. 0-4. 02. 7-4. 0 3. 4 0. 1-8. 0 3. 0-5. 0 4. 2 0. 1l. 5 0. 6-0. 9 08 BalanceBalance Balance Another advantageous nickel base alloy is:

Constituent Rangcto-Preferred range Example,

percent 2. 0-6. 0 3. 0-5. 0 3. 54 1. 0-4. 0 1. 5-2. 5 2. 02 0. 2-5. 0 0.3-1. 0 45 0. 01-0. 3 0. 01-0. 10 04 Bala ce Balance Balance Anotheradvantageous nickel base alloy is:

Constituent Rangctolrelerred range Example,

percent 1. 0-4. 0 1. 0-2. 5 1. 5 1. 0-0. 0 1. 0-4. 0 2. 6 0. 2-5. 0 0.2-1. 0 5 0. 01-0. 3 0. 01-0. 1 03 Balance Balance Balance What isclaimed is:

1. A homogenous ductile nickel base alloy weld deposit of uniformhardness formed from a metal powder mixture consisting essentially of anickel base alloy powder and nickel powder mixed with said alloy powderto provide a heterogeneous mixture, said nickel powder being in therange of 10 to 50% by weight of said mixture, said mixture having thecharacteristic of said nickel powder being completely soluble in saidnickel base alloy powder whereas said nickel base alloy deposit has alower hardness than said nickel base alloy powder in said heterogeneousmixture.

2. A process for depositing a nickel alloy composition upon a base metalcomprising the steps of adding nickel powder to a nickel base alloypowder having a relatively lower melting temperature, maintaining saidmixture heterogeneous and thereby including separate particles of saidpowders, said added nickel powder ranging approximately from 10 to 50%by weight of said heterogeneous mixture, and simultaneously spraying andfusing said heterogeneous mixture upon said base metal at a temperatureabove the said melting temperature of said nickel base alloy powder andbelow the melting temperature of said nickel powder to obtain ahomogeneous nickel alloy composition deposit upon said base metal havinga remelting temperature higher than the temperature at which it issimultaneously sprayed and fused.

3. A metal powder mixture as set forth in claim 1 wherein said nickelpowder has a particle size finer than mesh.

4. A metal powder mixture as set forth in claim 3 wherein said nickelpowder has a particle size less than 200 mesh and greater than 400 mesh.

5. A process as set forth in claim 2 wherein the particle size of saidnickel powder is maintained finer than 150 mesh.

6. A process as set forth in claim 5 wherein the particle size of saidnickel powder is maintained less than 200 mesh and greater than 400mesh.

7. A metal powder mixture as set forth in claim 1 wherein said nickelpowder is in the range of 30 to 40% by weight of said mixture.

8. A metal powder mixture as set forth in claim 1 wherein said nickelbase alloy consists essentially of the following constituents in theindicated ranges of percentages by weight:

Constituent: Range Silicon 2.0-6.0 Boron 1.0-4.0

Iron 0.2-5.0

Carbon 0.0l-0.3

Nickel Balance 9. A nickel base alloy metal powder as set forth in claim8 wherein said ranges of percentages by weight are:

Constituent: Range Silicon 3.0-5.0

Boron 1.5-2.5

Iron 0.3-1.0

Carbon 0.01-0.10

Nickel Balance 10. A metal powder mixture as set forth in claim 1wherein said nickel base alloy consists essentially of the followingconstituents in the indicated ranges of percentages by weight:

11. A nickel base alloy metal powder as set-forth in claim 10 whereinsaid ranges of percentages by weight are:

Constituent: Range Boron l.0-2.5

Silicon l.0-4.0

Iron 0.2-1.0

Carbon 0.01-0.l Nickel Balance 12. A process as set forth in claim 2wherein said nickel 6 powder is maintained in the range of to byConstituent: Range weight of said mixture. Boron 1.0-4.0 13. A processas set forth in claim 2 wherein said nickel Silicon 1.0-6.0 base alloyconsists essentially of the following constituents Iron 0.2-5 .0 in'theindicated ranges of percentages by weight: Carbon 0.010.3 Constituent:Range Nlckel Balance Silicon 2.0-6.0 16. A process as set forth in claim15 wherein said Boron 1.0-4.0 ranges of percentagesby weight are: Iron0.2-5.0 Carbon 001-03 10 g Range ron 1.02.5 Nlckel Balance Silicon 14. Aprocess as set forth in claim 13 wherein said Iron ranges of percentagesby weight are: Carbon 0 1 Nickel Balance Constituent: Range Silicon "rReferences Cited by the Examiner Boron 1.5-2.5 Iron UNITED STATESPATENTS carbon 0 01 0 10 2,868,667 1/1959 Bowles -171 Nickel Bala e2,936,229 5/1960 Shepard 7s 15. A process as set forth in claim 2wherein said nickel base alloy consists essentially of the followingconstituents in the indicated ranges of percentages by weight:

DAVID L. RECK, Primary Examiner.

WINSTON A. DOUGLAS, Examiner.

25 C. M. SCHUTZMAN, Assistant Examiner.

1. A HOMOGENOUS DUCTILE NICKEL BASE ALLOY WELD DEPOSIT OF UNIFORMHARDNESS FORMED FROM A METAL POWDER MIXTURE CONSISTING ESSENTIALLY OF ANICKEL BASE ALLOY POWDER AND NICKEL POWDER MIXED WITH SAID ALLOY POWDERTO PROVIDE A HETEROGENEOUS MIXTURE, SAID NICKEL POWDER BEING IN THERANGE OF 10 TO 50% BY WEIGHT OF SAID MIXTURE, SAID MIXTURE HAVING THECHARACTERISTIC OF SAID NICKEL POWDER BEING COMPLETELY SOLUBLE IN SAIDNICKEL BASE ALLOY POWDER WHEREAS SAID NICKEL ALLOY DEPOSIT HAS A LOWERHARDNESS THAN SAID NICKEL BASE ALLOY POWDER IN SAID HETEROGENEOUSMIXTURE.